Injector



Dec. 4, 1934.

J. F. GRIFFIN INJECTOR Filed June 7, 1952 A TTORNEYS.

Patented Dec. 4, 1934 INJECTOR Joseph F. Griflin, Teaneck, N. J assignorto The Superheater Company, New York, N. Y.

Application June 7, 1932, Serial No. 615,855

8 Claims.

n The present invention relates to injectors and has particularreference to injectorsof the type provided with fluid pressure actuatedcontrol systems. to water valve actuating mechanism and still moreparticularly, the invention relates to water valve actuating mechanismfor exhaust steam injectors.

In many forms of injectorcontrol systems as heretofore employed, thewatervalve of the injector is opened by means of a fluid pressureactuated piston in communication with a source of high pressure steam.In the forms of apparatus heretofore employed, the valve operatingpiston has been mounted in a suitable chamber in the injector body andhas operated a valve stem or plunger to open the water valve. In'orderto prevent leakage of steam around the actuating piston to the waterspace of the injector, such pistons have heretofore been provided withseats engaging a part of the injector body to prevent such leakage andfurther precaution has been taken by the provision of a vent between theseat and the water space of the injector through which steam can leak toatmospherein case a seat is not steam tight.

With the arrangements hitherto employed, numerous practical operatingdifliculties have been found to exist. Thus, for example, leakage ofwater frequently occurs due to a worn or badly fitted stem or plungerfor operating the water valve and such leakage has led to serious damageto the actuating mechanism, particularly in the case or" locomotiveinjectors in which in many instances water which has leaked into thechamber for the actuating piston has frozen when the injector was not inoperation. Freezing of water in this part of the apparatus has not onlyrendered it inoperative but has also in many instances cracked theinjector body and necessitated the replacement of the entire body of theinjector.

It is the general object of the present invention to provide an improvedform of valve operating mechanism. particularly for water valves whichwill eliminate the difiiculties heretofore encountered.

The nature of the invention and the more detailed objects thereof willbe more fully set forth in theensuing description of a preferred em-More particularly the invention relates.

jector. having a water valve operating mechanism embodying the inventionand Fig. 2 is a half section taken on the line 2-2 of Fig. 1.v 1

Referring now. to the drawing, 10 designates the injector body in whichis mounted the main steam nozzle 11 and the water nozzle 12.

'In the specific form of injector illustrated, which is of the exhauststeam type, low pressure steam is admitted to the chamber 13. This steammay be either exhaust steam admitted through valve 14 or it may beauxiliary live steam at low pressure admitted through conduit 15 to thechamber 16,-the latter communicating with chamber 13 by way of ports1"]. Supplementary high pressure steam is admitted through conduit 18 tothe chamber 19 which is in communication with the high pressure steamnozzle 20. r

The body of the injector provides a water space 21 which it will beobserved is in communication with the water nozzle 12. The admission ofwater to space21 is controlled by watervalve 22, water being admitted tothis valve through conduit 23. Valve 221s of the poppet type and seats,as shown, in .the directionof water flow to the injector and isadvantageously loaded by means of a light spring 24.

The valve actuating mechanism for opening valve 22 comprises a casing 25detachably secured to the body 10 as by means of bolts 26 andprojectinginto the water space 21. It will be observed that this casingwhen in position forms in effect a part of the injector body.

. Casing 25 has a bore therethrough comprising a portion 27 ofrelatively large, diameter and a portion 28 of smaller diameter. Theportion 28 provides a guide for a plunger element 29 having an enlargedportion or head 30 adapted to seat against a seat 31 provided by theshoulder at the outer end of the portion 28 of the bore. A piston 32 isslidably mounted in a large diameter portion 27 of the bore and isadapted to engage a seat 33 provided at the end of this portion of thebore. Piston 32 is guided by means of a stem 34 which is slidablymounted in a suitable recess 35 in plunger 29 and is advantageouslyfurther guided by a downwardly projecting stem 36 passing through anapertured web 3'7 in cap 38 which provides aclosure for the bottom ofcasing 25. A spring 39 is located around stem 34 between piston 32 andthe head 30 of the plunger 29. A vent 40 leading to atmosphere or otherzone of low pressure is provided in the wall of the casing 25 andcommunicates with the bore in the casing between the spaced seats 31 and33. The

upper end of the cap 38 provides a stop for piston 32 and a passage 41serves to connect the space below the piston with the chamber 19 towhich high pressure supplementary steam is admitted.

The operation of the apparatus is as follows:

When the injector is not in operation, the apparatus assumes theposition shown in Fig. 1 with the water valve 22 seated due to theaction of spring 24 and also due to the static head of Water acting onthe valve in case the supply tank to which conduit 23 is attached is ata level higher than the level of the injector. preciated that ifdesired, the spring 24 may be omitted, particularly in installationswhere a con-' siderable static hydraulic head is normally exerted onvalve 22. With the injector not in operation no pressure is exertedbelowpiston 32 and this piston, the plunger 29 and the associated springdrop to the position shown due togravity. In case the mechanism isplaced in a horizontal position rather than in a vertical position asshown, a suitable retracting spring may be employed if desired. I

When operation of the injector is started, steam is admitted throughsupply pipe 18 and passes through passage 41 to the space below piston32, lifting this piston and the plunger 29. Spring 39 is sufficientlystronger than spring 24 to overbalance' the static hydraulic'head onvalve 22 so that when the plunger 29 is moved upwardly, due to movementof piston 32 and through the medium of spring 39,-into contact withvalve 22, the valve is opened against the forces tending to seat it.Piston 32 and plunger 29 move upwardly without relative movement untilcontact is made between the plunger and the valve and this movement iscontinued until the head of plunger 29 seats against seat 31. As will beobserved from the drawing, the normal unstressed length of spring 39 isgreater than the distance between seats 31 and 33 so that when theplunger seats the piston 32 is still unseated. Piston 32 continues itsupward movement after the seating of plunger 29, until it seats againstseat 33-. This continued movement of the piston is possible due to theresilience afforded by spring 39.

With the parts in operative position when the injector is in operation,steam leakage past piston 32, which advantageously is not a steam tightfit in the bore 27, is prevented by the seating of the piston againstseat 33. Likewise, leakage of water through the portion 28 of the borearound the plunger 29 is prevented by the seating of head 30 againstseat 31. As will be observed from the drawing, the head 30 of plunger 29passesthe point where vent passage 40 communicates with the bore beforeit reaches its seat. Thus this vent passage communicates with the boreat a point which permits the Vent todischarge any steam which may leakpast the seat 33 due to wear or other imperfection in the seat and toalso discharge water which may pass seat 31 in case of an imperfect fitat this point.

Particularly in the case of exhaust steam injectors, it is highlyimportant that the temperature of the water reaching the water nozzle beas low as possible and leakage of water valve operating steam into thewater space ahead of the nozzle should be particularly guarded against.The present construction provides complete protection against leakagebecause of the two seats 33 and 31 which steam would have to pass beforeit could reach chamber 21, even if the vent 40 became clogged. Likewise,the leakage of water into the valve operating casing is guarded againstIt will be ap by structure providing a double seat. The resilientconnection between piston 32 and plunger 29 insures proper seating ofboth of these members against their respective seats and eliminates thedifficulties of maintaining the two parts in proper simultaneousengagement with their seats which would be encountered if the two partswere rigidly connected to each other. i

If for any reason water should find its Way into the casing 25 anddamage it due to freezing, the arrangement shown permits the readyreiiieval and replacement of the damaged parts without interfering inany way with the rest of the injector structure.

, A drain cock 42 may advantageously be provided to enable the smallquantity of moisture to be drained from cap 38 which may collect thereindue to condensation of operating steam below piston 32.

While the invention has been illustrated as applied to one specific typeof injector, it will be apparent that the invention is not limited inits application to the type of injector which has been chosen forpurposes of illustration but may equally Well be applied to other typesof injectors. It will also be evident that the specific valve operatingstructure which has been illustrated may be modified in various wayswithout departing from the invention.

What I claim is:

1; In an injector having a water nozzle, an inje'ct'or body providing awater space in communication with said nozzle, said body comprising awall having a bore therethrough communicating with said space, a valvefor admitting water to said space and means for opening said valvecomprising a fluid pressure actuated piston seat ing against a portionof said wall to prevent leakage of actuating fluid past the piston whenthe valve is open, and an intermediate element slidabl ymounted in saidbore and actuated by said piston to open said valve, said intermediateele ment seating at the outer end of said bore when the valve is open toprevent leakage of water from said space to the space in which saidpiston operates.

2. In an injector having a water nozzle, an injector body providing awater space in communication 'with said nozzle, said body comprising awall having a bore therethrough communicating with said space and avalve seat at the outer end of the bore and means for epenihg said valvecomprising an element having a, portion slidably mounted in said boreand a head having a face adapted to engage said seat when the valve isopen, a fluid actuated piston and a spring interposed between saidpiston and said element for transmitting motion f-rom the piston to theelement, said spring acting to seat said element and to maintain it inseated position when the piston is actuated to open the valve.

3. In an injector having a Water nozzle, an injector body providing awater space in communication with said nozzle, said body comprising awalled portion pr'dviding an inlet for admitting water to said spacearise wall portion opposite said inlet having a bore therethrou'gh and avalve seat at the outer end of the bore, a poppet valve for controllingsaid inlet, a plunger slidably mounted in said bore and having a headengaging said seat to prevent leakage of water through said'bore te theexterior of said space when the valve is open, a fluid actuated piston,and a, spring interposed between said piston and the head of saidplunger for seating the plunger and main taining it in seated positionwhen the piston is actuated.

i. In an injector having a water nozzle, an injector body providing awater space in communication with said nozzle, said body comprising aWall portion having a differential bore therethrough, said bore havingan inner portion of relatively small diameter, an outer portion ofrelatively large diameter and an intermediate portion of intermediatediameter, and there being valve seats between the portions of differentdiameter, a valve for admitting water to said space, a plunger slidablymounted in the portion of said bore of relatively small diameter, saidplunger being adapted to open said valve and having a head adapted toengage the seat between the portion of the bore of relatively smalldiameter and the portion of the bore of intermediate diameter, a fluidpressure actuated piston located in the portion of the bore ofrelatively large diameter, said piston being adapted to engage the seatbetween the portion of the bore of intermediate diameter and the portionof the bore of relatively large diameter, and a spring between saidpiston and said element for transmitting motion from the piston to theelement and for maintaining the element in seated position when thepiston is moved to engage its seat.

5. In an injector having a water nozzle, an injector body providing awater space in communication with said nozzle, said body comprising awall portion having a differential bore therethrough, said bore havingan inner portion of relatively small diameter, an outer portion ofrelatively large diameter and an intermediate portion of intermediatediameter, and there being valve seats between the portions of differentdiameter, a valve for admitting water to said space, a plunger slidablymounted in the portion of said bore of relatively small diameter, saidplunger being adapted to open said valve and having a head adapted toengage the seat between the portion of the bore of relatively smalldiameter and the portion of the bore of intermediate diameter, a fluidpressure actuated piston located in the portion of the bore ofrelatively large diameter, said piston being adapted to engage the seatbetween the portion of the bore of intermediate diameter and the portionof the bore of relatively large diameter, and a spring between saidpiston and said element for transmitting motion from the piston to theelement and for maintaining the element in seated position when thepiston is moved to engage its seat, there being a vent passage providingcommunication between the portion of the bore of intermediate diameterand a zone of low pressure.

6. In an exhaust steam injector having a body and a water valve seatingin said body, means for opening said valve comprising a casingdetachably secured to said body, said casing having a difierential borecomprising a portion of relatively small diameter, a portion ofrelatively large diameter and an intermediate portion of intermediatediameter, a valve actuating plunger mounted in the portion of relativelysmall diameter, said plunger having a head adapted to engage a seat insaid casing between the portion of the bore of relatively small diameterand the portion of the bore of intermediate diameter, a piston mountedin the portion of the bore of relatively large diameter, said pistonbeing adapted to engage the seat between the portion of the bore ofrelatively large diameter and the portion of the bore of intermediatediameter, means for admitting pressure fluid to the portion of the boreof relatively large diameter to move said piston to its seat and aspring between said piston and said plunger for moving the latter to itsseat when the piston is seated.

'7. Water valve operating mechanism for injectors comprising a casingadapted to be detachably secured to an injector body, said casing havinga bore therethrough having portions of different diameter, a pistonmounted in a portion of larger diameter, a plunger adapted to contact avalve part and mounted in a portion of smaller diameter, and a springbetween said piston and said plunger, said portions of said boreproviding two axially spaced seats, one of said seats being at the endof said portion of the bore of smaller diameter, said plunger beingadapted to engage the seat at the end of the portion of the bore ofsmaller diameter to prevent leakage of fluid into said casing, and saidpiston being adapted to engage, the other of said seats to preventleakage of actuating fluid past the piston.

8. In an injector having a water nozzle, an injector body providing awater space in communication with said nozzle, said body comprising awall having an opening for admitting water to said space and a separablecasing detachably secured to the main portion of the body opposite saidopening, a water valve of the poppet type for controlling the flow ofWater through said opening and fluid pressure actuated means for openingsaid valve located in said casing and comprising a fluid pressureactuated piston and an element actuated by said piston for opening thevalve, said element being separate from and movable relative to saidpiston and comprising a portion seating against the wall of the casingto prevent leakage of water from the water space of the injector to theinterior of the casing.

JOSEPH F. GRIFFIN.

